Clock



FIG. 1 is a perspective view of a clock showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a left side view thereof; and,

FIG. 4 is a right side view thereof.

The structural features depicted by broken lines in FIGS. 3 and 4 have been shown for the purpose of illustrating portions of the clock that form no part of the claimed design. 

CLAIM The ornamental design for a clock, as shown and described. 